This disclosure relates to a speaker. International patent application PCT/US2013/039815 discloses a deployable speaker that includes a driver and an acoustic enclosure made up of a multiplicity of panels. The driver is secured to one of the panels. The acoustic enclosure is deployable from a closed state to a deployed state. When one of the panels is moved by a user from the closed to the deployed state, all but one of the remaining panels are simultaneously moved from the closed to the deployed state.
It is desirable to make the deployable speaker as compact as possible when it is in the closed state. One way to achieve this goal is to have any passive radiator included in the speaker be thin in a direction perpendicular to a plane in which the passive radiator lies. Existing passive radiators incorporate heterogeneous surrounds that restrict how compact a deployable speaker can be when the speaker is in a closed state.